Praise be to Allah.
With regard to the secretions that occur in women when pregnant and otherwise, if they come from the uterus – which is usually the case – they are taahir (pure), but if they come from the urethra, then they are impure (najis).
These secretions do not necessitate ghusl, but they do invalidate wudoo’, unless they are ongoing and do not cease, in which case they come under the same rulings as incontinence, so wudoo’ must be done for each prayer after the time for prayer begins.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said: What appears to me to be the case after studying the matter is that the fluid that is emitted by a woman, if it does not come from the urethra and in fact comes from the uterus, is pure (taahir).
This is the ruling on these secretions with regard to purity (tahaarah): they are pure (taahir) and do not make the clothing or body impure (najis).
With regard to the ruling when it comes to wudoo’, this secretion invalidates wudoo’ unless it is continual, in which case it does not invalidate wudoo’, but the woman should not do wudoo for prayer until after the time of the prayer has begun and she has taken protective measures.
But if it stops and starts, and it usually stops during the times of prayer, then she should delay the prayer until the time when it stops, so long as she does not fear that the time for the prayer will end. If she is afraid that the time for prayer will end, then she should do wudoo’ and take protective measures and pray. It makes no difference whether the discharge is small or great, because it is all coming from the same place, so either a little or a lot of it invalidates wudoo’.
End quote from Majmoo‘ Fataawa Ibn ‘Uthaymeen (11/284)
What is meant by “taking protective measures” is that she should put a piece of cloth or cotton or the like over her private part so that it will absorb whatever comes out of this fluid and prevent it spreading on her garments or body.
And Allah knows best.